Alternator Replacement PDF

# 10-4. Alternator Replacement ## Non-Overhaul Repair and Replacement Replace the alternator when it fails to deliver the correct voltage and amperage to the aircraft electrical system. If electrical malfunctions are isolated to the alternator, physical inspection of the alternator must be accompl...

# 10-4. Alternator Replacement ## Non-Overhaul Repair and Replacement Replace the alternator when it fails to deliver the correct voltage and amperage to the aircraft electrical system. If electrical malfunctions are isolated to the alternator, physical inspection of the alternator must be accomplished before replacement. The engine may be equipped with a direct drive alternator, a belt-driven alternator, or both. For Continental alternators, refer to Table 1-2 for the appropriate instructions to service or overhaul the alternator. Consult Section 10-4.3 for applicable continued airworthiness instructions or replace the alternator with a new, rebuilt, or serviceable alternator during the 500 hour inspection. On all GTSIO-520 and All 520 and 550 series engines with a Permold crankcase, a gear driven alternator pad, forward of the No. 5 cylinder is driven off the crankshaft face gear. In this manual, these alternators are designated as **FWD**. See Section 10-4.1 for removal and installation instructions. C-75, C-85, C-90, C-115, C-125, C-145, E-165, E-185, E-225, O-200, GO-300, GIO-300, O-300, IO-240, IOF-240, and all 360 series engines feature an alternator mounting pad on the accessory case, driven off the camshaft gear. These alternators are designated as **AFT** in this manual; see Section 10-4.2 for removal and installation instructions. ## 10-4.1. Gear Driven Alternator Replacement, Forward Mount **FWD** ### 10-4.1.1. Gear Driven Alternator Removal **FWD** #### Applicable Engines: - IO-520-B, BA, BB, C, CB, M, MB, NB, TSIO-520-B, BB, BE, D, DB, E, EB, J, JB, K, KB, L, LB, N, NB, UB, VB, WB, IO-550-A, B, C, G, N, P, R, IOF-550-N, P, R, TSIO-550-В, С, E, G, K, N, TSIOF-550-D, J, K, P, TSIOL-550, A, B, C **WARNING** - Turn the Ignition Switch **OFF** and disconnect engine electrical power before commencing maintenance or inspections. - Confirm continuity between the magneto capacitor and aircraft ground to prevent accidental engine start during maintenance. - Do not stand or place equipment within the arc of the propeller. 1. Turn the Ignition Switch to the **OFF** position and disconnect engine electrical power. 2. Disconnect the aircraft battery according to the aircraft manufacturer's instructions. 3. Disconnect electrical connections from the alternator according to the aircraft manufacturer's instructions. 4. Remove the nut, washer, lock washer, and from the four alternator mounting studs; discard the lock washers. 5. Remove the alternator from the crankcase mounting studs. **CAUTION**: Exercise care when cleaning the residue from the mounting flange; mask the crankcase opening to avoid contaminating the engine oil supply. 6. Remove and discard the gasket; clean any remaining gasket residue from the crankcase flange with lacquer thinner. 7. Place the alternator in a horizontal position, rotate the shaft in both directions. If the shaft does not turn freely, rotor friction or bearing stress is indicated, or noticeable shaft displacement is detected during rotation, replace the alternator. 8. Perform a "Gear Tooth Inspection" on the alternator drive coupling gear according to the instruction in Section 11-1.1. If the drive coupling gear teeth are chipped, broken, or otherwise damaged, replace the drive coupling according to instructions in Section 10-4.1.2 and perform a "Foreign Object Contamination Inspection" according to instructions in Section 6-5.7. 9. Inspect the drive coupling for serviceability. If the coupling exhibits damage or missing material, replace the drive coupling and perform a "Foreign Object Contamination Inspection" according to instructions in Section 6-5.7. 10. Perform a "Gear Tooth Inspection" on the alternator face gear according to the instruction in Section 11-1.1. If the face gear teeth are chipped, broken, or damaged, disassemble the engine and replace the crankshaft face gear. 11. Perform an "Alternator Drive Coupling Inspection" according to instructions in Section 6-4.22.1. **Figure 10-4. Alternator and Drive Coupling** ### 10-4.1.2. Alternator Drive Coupling Removal **FWD** #### Applicable Engines: - IO-520-B, BA, BB, C, CB, M, MB, NB, TSIO-520-B, BB, BE, D, DB, E, EB, J, JB, K, KB, L, LB, N, NB, UB, VB, WB, IO-550-A, B, C, G, N, P, R, IOF-550-N, P, R, TSIO-550-B, C, E, G, K, N, TSIOF-550-D, J, K, P, TSIOL-550, A, B, C 1. Remove the alternator from the crankcase according to the instructions in Section 10-4.1.1. **CAUTION**: Remove and discard the spring coupling (Part No. 6409333 or 640934) if installed on the alternator. The elastomer coupling superseded the spring couplings. 2. Remove and discard the cotter pin and remove the castellated nut. 3. Remove the drive coupling assembly from the alternator shaft. 4. Separate the thrust washer and drive hub assembly. 5. Inspect, disassemble, troubleshoot, repair, and assemble Continental alternators according to the Alternator Service Instruction (X30531). Reference the manufacturer's primary ICAs for all non-Continental alternators. **NOTE**: If the alternator is manufactured for Continental by Hartzell Engine Technologies, HET (dba Plane Power) consult Section 10-4.3 for applicable airworthiness instructions. For all non-Continental alternators, replace the alternator with a new, rebuilt, or serviceable unit. ### 10-4.1.3. Alternator Drive Coupling Installation **FWD** #### Applicable Engines: - IO-520-B, BA, BB, C, CB, M, MB, NB, TSIO-520-B, BB, BE, D, DB, E, EB, J, JB, K, KB, L, LB, N, NB, UB, VB, WB, IO-550-A, B, C, G, N, P, R, IOF-550-N, P, R, TSIO-550-B, C, E, G, K, N, TSIOF-550-D, J, K, P, TSIOL-550, А, В, С **WARNING** - If the shipping washer is not removed prior to installing the drive coupling, the shipping washer will interfere with the crankshaft face gear and damage the engine and alternator. 1. Remove the shipping spacer and washer from the alternator shaft and discard to prevent interference with the crankshaft face gear. **WARNING** - The thrust washer must be installed with the bearing surface (copper color) facing the alternator. 2. Install the drive coupling, and new thrust washer on the alternator shaft. **NOTE**: Hartzell alternator drive shafts manufactured after April 2014 feature a hex drive to facilitate securing the shaft. 3. Install the castellated nut on the shaft. Secure the drive coupling with a 5/16" hex key wrench or an Alternator Drive Hub Spanner Wrench (see Section 2-1, "Special Tools") and torque the castellated nut to the minimum value specified in Appendix B. 4. If the slots of the nut do not align with the cotter pin hole in the alternator shaft, the castellated nut may be torqued up to the maximum value in Appendix B. If the cotter pin holes will not align with the nut slot within the torque range, replace the nut. 5. Install the new cotter pin according to the “Cotter Pin Installation" instructions in Section C-7, cut and bend the cotter pin according to the illustration in Figure 10-4 to prevent it from touching the thrust washer and to attain clearance when installing the alternator on the engine. 6. After drive coupling installation, inspect the drive coupling assembly for slippage according to the instructions in Section 10-4.1.4. 7. Install the alternator according to "Gear Driven Alternator Installation" instructions in Section 10-4.1.5. ### 10-4.1.4. Alternator Drive Coupling Slippage Inspection **FWD** **NOTE**: Do not remove the drive coupling for the slippage inspection. Secure the alternator shaft as instructed below. 1. Secure the alternator in a shielded vise to prevent movement. Do not over-tighten. **CAUTION**: Secure the outer diameter of the drive coupling assembly. Allow the gear freedom of movement to prevent damaging or shearing the elastomer coupling. 2. Secure the alternator drive coupling with a 5/16" hex key wrench or an “Alternator Drive Hub Spanner Wrench (Table 2-1); adjust the bolts using finger pressure only - do not torque the bolts. **Figure 10-5. Alternator Drive Hub Spanner Wrench** 3. Measure drive coupling slippage using an "Alternator Drive Hub Torque Tool" (Figure 2-5) and currently calibrated torque wrench set to value for the drive coupling condition specified in Table 10-4. Turn the hub through a 45° arc at a rate of 1° to 2° per second. No slippage is permitted below the value specified in Table 10-4. 4. If the coupling slips with less torque applied than the value specified in Table 10-4, or the coupling exhibits physical damage, discard and replace the alternator elastomer drive coupling and repeat the slippage check on the new drive coupling. **Table 10-4. Alternator Drive Coupling Slippage** | Coupling Assembly Condition | Slippage Prohibited Below: | |:---|:---| | New coupling or coupling with less than 25 hours in service | 180 in-lbs. | | Coupling with more than 25 hours in service | 140 in-lbs. | ### 10-4.1.5. Gear Driven Alternator Installation **FWD** #### Applicable Engines: - IO-520-B, BА, ВВ, С, СВ, M, MB, NB, TSIO-520-B, BB, BE, D, DB, E, EB, J, JB, K, KB, L, LB, N, NB, UB, VB, WB, IO-550-A, B, C, G, N, P, R, IOF-550-B, C, N, P, R, TSIO-550- B, C, E, G, K, N, TSIOF-550-D, J, K, P, TSIOL-550, A, B, C Prior to alternator installation, perform an "Alternator Drive Coupling Slippage Inspection" in Section 10-4.1.4 and install a serviceable drive hub according to instructions in Section 10-4.1.3. **WARNING** - Turn the Ignition Switch **OFF** and disconnect engine electrical power before commencing maintenance or inspections. - Confirm continuity between the magneto capacitor and aircraft ground to prevent accidental engine start during maintenance. - Do not stand or place equipment within the arc of the propeller. **CAUTION**: If the removed alternator exhibited gear tooth or elastomer coupling damage, the engine must be inspected for foreign object contamination prior to installing a new alternator. 1. Turn the Ignition Switch to the **OFF** position and disconnect engine electrical power. 2. Perform a "Gear Tooth Inspection” on the alternator face gear according to the instruction in Section 11-1.1. If the face gear teeth are chipped, broken, or damaged, disassemble the engine and replace the crankshaft face gear. 3. Install a new gasket on the alternator mounting studs. 4. Install the alternator on the mounting studs using four new lock washers, four plain washers and four nuts.Torque the nuts to 150-180 in. lbs. in an alternating cross pattern. 5. If the alternator had a grounding strap when it was removed, install the grounding strap when installing the alternator. 6. Reconnect electrical connections at the alternator according to the aircraft manufacturer's instructions. 7. Consult the aircraft maintenance manual for instructions to reconnect ram air ducts, if equipped, for alternator cooling air. 8. Reconnect the aircraft battery according to the aircraft manufacturer's instructions. 9. Start the engine ("Engine Start" instructions in Section 7-3.2) and test the alternator output according to the instructions in the Aircraft Maintenance Manual.